HEAT AND MASS TRANSFER IN DISPERSE AND POROUS MEDIA

SIMULATION OF THE TRANSFER

OF WATER WITH A FINE-DISPERSE

GAS PHASE IN POROUS MEDIA

A. Yu. Dem’yanov,^{a} O. Yu. Dinariev,^{b}

and E. N. Ivanov^{b}

UDC 532.5

The problem on the transfer of a three-phase water–gas–oil mixture in a porous medium was solved for the

case where the water contains a fine-disperse gas phase in the form of microsized or nanosized bubbles. It

was suggested that the transfer of bubbles is mainly due to the flow of the disperse phase (water). In this

case, the large aggregates of the gas phase in the porous space, in the water, and in the oil are transferred

in accordance with the modified Darcy law for multiphase mixtures. A mathematical model of movement of

the indicated mixture has been constructed for the case where the main phases (water, gas, and oil) adhere

to the filtration equations and the fine-disperse gas phase is defined by a kinetic equation like the Boltzmann

equation. Some one-dimensional numerical solutions of the indicated problem were analyzed.

Keywords: fine-disperse gas, filtration in a porous medium, kinetic equation.

PAGE 1243

ON THE PROBLEM OF EVALUATION OF HYDRAULIC

DRAG OF POROUS STRUCTURES

F. P. Ivanov

UDC 532.546

A comparative analysis of the coefficients of hydraulic drag in coolant flow in sintered porous structures is

performed. Equations for appraisal calculations are recommended.

Keywords: heat transfer, sintered porous structures, hydraulic drag, coefficients of viscosity and inertia, specific

pressure drop, filtration.

PAGE 1254

ACCOUNT OF THE COMPRESSIBILITY OF THE SOLID

PHASE IN GAS FLOW THROUGH POROUS MEDIA

N. S. Belyakov,^{a} N. A. Lutsenko,^{a,b}

S. S. Minaev,^{c} and Yu. S. Teplitskii^{d}

UDC 532.546.7

A study is made of the problem of taking account of the compressibility of the solid phase at high pressures

in problems of gas flow through porous media for linear filtration and nonlinear filtration alike. For this purpose,

the problems of one-dimensional steady-state gas flow through a porous medium have been solved and

analyzed for a compressible and an incompressible solid porous skeleton at a known pressure difference. It

has been shown that in taking account of the compressibility, the maximum relative deviations of the sought

quantities from the value calculated disregarding it depend linearly, as a rule, on the compressibility factor

and the pressure of the gas at entry into the porous medium. However in the case of nonlinear filtration, in

media with a high permeability, taking account of the compressibility is also influenced by the filtration coefficient

and by the inertial coefficient of drag of the porous medium. Nonlinear dependences of the maximum

relative changes in the sought quantities on the problem’s parameters arise.

Keywords: filtration of a gas, porous medium, compressibility.

PAGE 1259

CALCULATION OF THE EFFICIENCY

OF CIRCULAR POROUS CHANNELS

BY THE MODIFIED GUHMAN METHOD

A. P. Lukisha

UDC 536.2:532.5

Results of calculation of the efficiency of circular porous channels in the transient region 2300 ≤ Resm ≤

10,000 of movement of an incompressible coolant (water) in smooth-wall channels compared with the porous

channels at the first-kind boundary conditions are presented. The efficiencies of circular porous channels and

smooth-wall ones were compared using the modified Guhman method, in accordance with which the efficiency

of a short porous channel, in which a coolant is rapidly heated, is determined by comparison of this channel

with a long smooth-wall channel. As a criterion for selection of the length of a circular porous channel, the

attainment of the value 0.8 by the average dimensionless temperature of the liquid at the output of this channel

was used. The influence of different design and regime parameters of the channels being compared on

their efficiencies was investigated and the parameters, at which the gain in heat transfer superpasses the loss

in hydraulics, were determined.

Keywords: efficiency, porous channels, the transient region between the laminar and turbulent regimes of movement

of an incompressible coolant, the first-kind boundary conditions.

PAGE 1266

CENTRIFUGAL DEWATERING AND DRYING

OF HIGH-MOISTURE WOOD

V. P. Kozhin

UDC 674.049:532.5

The results of investigation of centrifugal dewatering and rotation-convection drying of water-saturated wood

which stayed under water for a few decades are presented.

Keywords: centrifuge, dewatering, drying, wood, submerged.

PAGE 1278

VIBRORHEOLOGICAL MODEL OF THE

VIBROFLUIDIZED BED OF DRY SUBSTANCES

S. A. Rusanov, K. V. Lunyaka,

and G. V. Nikitenko

UDC 66.01:66.011

Problems connected with theoretical aspects of the process of vibrofluidization of dry substances have been

considered. We present some theoretical results that make it possible to analyze more thoroughly the behavior

of dispersive materials in the process of vibrofluidization with account for the gas flow through the bed and

automatize the above calculations.

Keywords: vibrofluidized bed, two-phase flow, flow curves, numerical calculations, vibrorheology.

PAGE 1284

INFLUENCE OF VIBROWAVE ACTION

ON THE CHARACTER OF PRESSURE

DISTRIBUTION IN A BED

E. M. Abbasov and N. A. Agaeva UDC 532.546

The influence of different forms of elastic waves generated on the bottom hole on the character of pressure

distribution in the bed has been studied on the basis of theoretical investigations. The depth and dynamics of

propagation of the elastic waves in the bed as functions of the form of generated elastic waves have been determined.

Keywords: filtration, pressure, bed, vibrowave action, differential equation, Bessel function, period, fluid.

PAGE 1290

CARRY-OVER OF PARTICLES IN A CYCLONE CHAMBER

E. A. Pitsukha,^{a} Yu. S. Teplitskii,^{b}

and V. A. Borodulya^{b}

UDC 532.529

The carry-over of clay and crushed-rice particles in a cyclone chamber of diameter 0.393 m was experimentally

investigated for different heights of introduction of a polyfractional disperse material. The maximum diameter

of the carried particles was calculated in relation to the velocity of air at the output of the nozzles

and the diameter of the outlet (exhaust port) of the chamber. The influence of the bottom flow on the carryover

of particles in the indicated chamber was determined.

Keywords: cyclone chamber, carry-over of particles, maximum diameter of the carried particles, bottom blow,

incomplete combustion.

PAGE 1298

COMPARISON OF CALCULATIONS

BY THE TWO-FIELD VIBROFLUIDIZED-BED

MODEL WITH EXPERIMENTAL DATA

N. S. Orlova

UDC 519.87:66.096.5

A two-fluid vibrofluidized-bed model based on the Euler approach and Darcy law is investigated. Satisfactory

agreement of numerical calculations with experimental data on the change in the position of the lower boundary

of a thick layer of finely divided particles and of pressure in its lower part as functions of the vibration

phase of the shelf has been obtained.

Keywords: two-fluid model, vibrofluidized bed, Euler approach, Darcy law, gas pressure, numerical calculations.

PAGE 1305

THERMOMECHANICS OF THE GRANULAR

BED T-JOINT WATER HEATER

Yu. S. Teplitskii and D. G. Belonovich

UDC 532.5

On the basis of the heat transfer model taking into account the radiative transport the temperature distribution

and the resistance of the water heater with a granular packing having two independent air inlets have

been investigated. The generalized dependence for calculating the resistance of the granular bed has been

obtained.

Keywords: ring bed, air heater, heat transfer model, radiative heat transfer.

PAGE 1311

NUMERICAL MODELING OF A NONMONOTONIC

SEPARATION HYDROCYCLONE CURVE

L. L. Min’kova and J. H. Dueckb

UDC 532.542.4:575.5,519.63

In the context of the mechanics of interpenetrating continua, numerical modeling of separation of a polydisperse

suspension in a hydrocyclone is carried out. The so-called "mixture model" valid for a low volume fraction

of particles and low Stokes numbers is used for description of the suspension and particle motion. It is

shown that account taken of the interaction between large and small particles can explain the nonmonotonic

behavior of the separation curve.

Keywords: numerical modeling, hydrocyclone, separation function, "fish-hook" effect, accelerated settling of

small particles, polydisperse suspension.

PAGE 1317

NONSTATIONARY MASS TRANSFER IN A DRYING

CHAMBER–ADSORBER SYSTEM UNDER CONDITIONS

OF NONEQUILIBRIUM ADSORPTION OF STEAM

P. A. Vakul’chik,a V. K. Kulikovskii,b

N. V. Pavlyukevich,a and Yu. I. Aristovc

UDC 533.15:66.047

Simulation of filtration and nonequilibrium adsorption of steam in an adsorber and a comparison of calculated

and experimental data were carried out.

Keywords: adsorption, filtration, steam, isotherm, relaxation time.

PAGE 1327

HEAT AND MASS TRANSFER IN COMBUSTION PROCESSES

CHANGE IN THE REGIMES OF FLOW AND COMBUSTION

IN A CHANNEL UNDER EXTERNAL ENERGY ACTION

V. A. Zabaikin, I. E. Naumov,

and P. K. Tret’yakov

UDC 536.46

The influence of the energy impulse-periodic action on the structure of the hydrogen-air mixture flow in a

channel for going from the regime of diffusion combustion of the mixture to pseudojump-like combustion has

been investigated. Experiments were carried out in a rectangular channel with sections of variable and constant

cross-section. The energy input was controlled with the aid of a heat-gas-dynamic pulse generator in

which a hydrogen-air mixture was burned. The intensity and regimes of combustion were determined by the

flame radiation in the ultraviolet spectral region and static pressure measurements. In the course of experiments,

the possibility of going from diffusion to pseudojump-like combustion under periodic energy and kinetic

actions on the mixture flow has been confirmed.

Keywords: pseudojump-like regime, combustion, impulse-periodic and kinetic action, rectangular channel, heatgas-

dynamic pulse generator, optical recording.

PAGE 1331

PYROLYSIS OF BROWN COALS

OF THE LELCHITSY DEPOSIT

I. I. Lishtvan, P. L. Falyushin,*

V. M. Kraiko, and V. M. Dudarchik

UDC 662.813:732

Results of experimental studies on pyrolysis of brown coals of the Lelchitsy deposit, which were conducted on

Laboratory setups in stationary and moving layers for producing high-caloric energy carriers, are presented.

The yield of the pyrolysis products is determined; the chemical composition of solid, liquid, and gaseous

products of thermochemical treatment is considered.

Keywords: brown coal, pyrolysis, thermal decomposition, energy carriers, combustion heat.

PAGE 1339

CONCERNING THE PROBLEM OF DYNAMIC DAMPING

OF THE VIBRATION COMBUSTION SELF-OSCILLATIONS

IN A LIQUID-PROPELLANT ROCKET ENGINE

B. I. Basok,a V. V. Gotsulenko,a

and V. N. Gotsulenkob

UDC 629.7:533.6.001

The reason for the decrease in the amplitude of longitudinal vibration combustion self-oscillations in the combustion

chamber of a liquid-propellant rocket engine by means of antipulse partitions has been justified. A

mathematical model of the development of combustion instability in such a chamber on attachment of a Helmholtz

resonator to it has been obtained. The character of the damping of vibration combustion self-oscillations

excited by the action of the Crocco mechanisms and negative thermal resistance, when varying the acoustic

parameters of the resonator and of the pressure head characteristics of combustion chamber is established.

Keywords: vibration combustion self-oscillations, Helmholtz resonator, damping of self-oscillation, wave resistance,

antipulse partitions.

PAGE 1346

HYDROGASDYNAMICS IN TECHNOLOGICAL PROCESSES

MODULATION OF SOUND OSCILLATIONS

IN A FIELD WITH DISSIMILAR SOURCES

OF HYDRODYNAMIC PERTURBATIONS

R. K. Karavosov and A. G. Prozorov UDC 621.51:532; 533.6.071.4

Sound oscillations in the near field of the open working sections of two different wind tunnels are investigated.

It was established by measuring the spectra of pressure fluctuations that the amplitude modulation of

oscillations and the formation of their packets are typical of the cases considered. A more complete picture

of the transient regime of flow in the mixing layer of a free jet in the working section of a wind tunnel is

obtained. The well-known results of natural observations at the Sayano-Shushenskaya hydroelectric station are

interpreted.

Keywords: auto-oscillations, acoustic radiation, wind tunnel, Tollmien–Schlichting waves, hydroacoustic resonance,

infrasound, modulation, self-excitation, noise meter.

PAGE 1352

SIMULATION OF A TURBULENT SUPERSONIC

UNDEREXPANDED JET FLOWING INTO

A SUBMERGED SPACE WITH THE HELP

OF A SHEAR STRESS TRANSFER MODEL

S. A. Isaev,a Yu. M. Lipnitskii,b P. A. Baranov,c

A. V. Panasenko,b and A. E. Usachovd

UDC 532.517:4

We have calculated the flow of an axisymmetric turbulent supersonic underexpanded jet into a submerged

space with the help of the VP2/3 package as part of the generalized pressure correction procedure. The shear

stress transfer model modified with account for the curvature of streamlines has been verified on the basis of

comparison with V. I. Zapryagaev’s data obtained at the S. A. Khristianovich Institute of Theoretical and Applied

Mechanics, Siberian Branch of the Russian Academy of Sciences. The influence of the generated vortex

viscosity on the shock-wave structure of the jet, the field of flow parameters, and the turbulence characteristics

has been analyzed.

Keywords: shock-wave structure, supersonic underexpanded jet, turbulence, calculation, SST model, tube tests,

pressure correction procedure, SLAU, multiblock computational technologies, VP2/3 package.

PAGE 1357

CONTROL OF TRANSONIC FLOW PAST AIRCRAFT

ELEMENTS USING DIFFERENT EXTERNAL ENERGY

SOURCES

S. M. Aul’chenko, V. P. Zamuraev,

and A. P. Kalinina

UDC 533.6.011

A study has been made of the influence of pulsed-periodic energy supply on transonic regimes of flow past a

body of revolution for different source models. The possibility of restructuring significantly the flow has been

shown, which can serve as a basis for efficient control of flow past the entire aircraft and its elements alike.

Keywords: transonic flow, body of revolution, pulsed energy supply, Euler equations.

PAGE 1372

REDUCING THE WAVE DRAG OF WING AIRFOILS

IN TRANSONIC FLOW REGIMES BY THE FORCE ACTION

OF AIRFOIL SURFACE ELEMENTS ON THE FLOW

S. M. Aul’chenko and V. P. Zamuraev UDC 533.6.011

Mathematical modeling of the influence of forced oscillations of surface elements of a wing airfoil on the

shock-wave structure of transonic flow past it has been carried out. The qualitative and quantitative influence

of the oscillation parameters on the wave drag of the airfoil has been investigated.

Keywords: transonic flow past a wing airfoil, forced oscillations, wave drag.

PAGE 1378

SIMULATION OF THE HEAT EXCHANGE BETWEEN

THE SUPERSONIC FLOW AND THE STATIONARY

BODY IN A GAS CENTRIFUGE

K. V. Zvonarev, V. D. Seleznev,

V. I. Tokmantsev, and Yu. V. Abramov

UDC 621.039.31

We have made comparative calculations of the heat exchange in the subpersonic flow of gaseous UF6 around

the stationary cylindrical body inside the rotating rotor of the gas centrifuge. It has been revealed that the

integral heat flux from the gas to the body calculated with the use of the ANSYS-CFX program complex from

the viewpoint of the continuum model is much smaller than the heat flow calculated by the Monte Carlo

method of direct statistical simulation. Estimates show that under the conditions being considered the boundary

layer on the surface of the body has no time to be formed and has a thickness of the order of the mean

free path of the gas molecules and, therefore, the use of the methods of continuum mechanics in this region

is incorrect. On the contrary, the method of direct statistical simulation permits taking into account the interaction

of gas molecules directly with the surface of the streamline body and obtaining more correct results.

Keywords: gas centrifuge, ANSYS-CFX, Monte Carlo method, heat exchange, supersonic flow.

PAGE 1357

INVESTIGATION OF THE ACTION OF A TRANSVERSE

FLOW ON INJECTED NORMALLY VERTICAL ELEVATED

LOW-HEAD JETS

K. G. Dobrosel’skii UDC 533.6.071.4

The action of a turbulent air flow on injected normally vertical elevated low-head axisymmetric jets has been

investigated experimentally. Empirical formulas have been obtained for the geometry of the axes of isothermal

and slightly nonisothermal jets and for dimensionless velocities and temperatures in their cross sections. It

has been shown that the above jets are of a higher ejection ability in the transverse flow than submerged jets

and wakes.

Keywords: jet, flow, jet axis, velocity and temperature profiles.

PAGE 1390

BIFURCATION OF VISCOELASTIC FLUID COUNTERFLOWS

I. A. Makarov UDC 532.5.013.4:532.135

One of the phenomena of structural instability observed earlier in viscoelastic fluid flows in cross-channels,

namely, the asymmetry of flows in the region of the central singular point is considered. It is shown analytically,

by demonstrating symmetric and asymmetric asymptotic solutions in the vicinity of this singular point,

that the latter exhibits bifurcation. The fields of velocities and distributions of stresses and pressure provided

by asymptotic solutions are compared with their analogs observed experimentally and in numerical simulation.

Close association of the existence of asymmetric flows with the viscoelastic nature of fluid is shown.

Keywords: viscoelastic fluid, flow with a singular point, asymmetry, bifurcation.

PAGE 1397

ON AN INFLOW OF A MULTICOMPONENT

MIXTURE IN A VACUUM

V. S. Surov UDC 532.529.5

A self-similar problem on an inflow of a multicomponent mixture in a vacuum was solved for a multivelocity

model of a heterogeneous medium.

Keywords: multivelocity multicomponent medium, hyperbolic system of partial differential equations, self-similar

solution.

PAGE 1406

ANALYSIS OF THE TEMPERATURE DISTRIBUTION

IN THE EXPLOSION OF A METHANE/AIR MIXTURE

IN A TUNNEL

Qi Zhang and Lei Pang UDC 532.5

The aim of this work is to investigate temperature distribution in methane/air mixture explosion near a wall

of a tunnel by numerical simulation. The results obtained on the basis of the hypothesis of an adiabatic wall

are compared with those for a nonadiabatic wall. It is shown that the temperature near the wall in explosion

of methane/air mixtures in tunnels changes abruptly. The hypothesis of an adiabatic wall leads to a great

error in the calculated temperature near the wall. If heat conduction in the wall is ignored, the temperatures

at various locations of a section are almost equal, whereas the measured temperatures on the vessel wall are

always lower than those calculated on the basis of the hypothesis mentioned. However, when it is necessary

to find the temperatures in the field outside the range near the wall, heat conduction in it can be ignored.

Keywords: methane/air mixtures, temperature of explosion, numerical simulation, adiabatic wall.

PAGE 1413

ANALYSIS OF FREE OSCILLATIONS

OF THIN-WALLED CYLINDRICAL SHELLS

CONTAINING A COMPRESSIBLE LIQUID

A. I. Seifullaev, G. A. Mamedova,

M. A. Rustamova, and A. O. Yuzbasheva

UDC 539.3

Free oscillations of a thin-walled cylindrical cell containing a compressible liquid were investigated. At some

values of the parameters of the system, its eigenfrequencies were determined, and the influence of the geometric

and physical parameters of the cylindrical shell–liquid system on the free oscillation of cylinder was investigated.

Keywords: stress, oscillations, wave, frequency, density, shell.

PAGE 1419

NANOSTRUCTURES

STRUCTURE OF CARBON FILMS DEPOSITED

FROM A GAS DISCHARGE AT ATMOSPHERIC

PRESSURE

S. V. Shushkov,^{a} I. S. Krylov,^{a} S. V. Gusakova,^{b}

M. A. Silenkov,^{c} and S. A. Zhdanok^{a}

UDC 621.793.16+661.66

Carbon films were formed on anode (Ni, Cu) substrates from a low-current (10–100 mA) discharge in a

He/CH4 mixture at atmospheric pressure. In the case of deposition on substrates without heating, amorphous

films with a submicron fractal structure of the surface are formed. Films grown on a heated (1000oC) substrate

have a sandwich graphitized structure.

Keywords: gas discharge, plasma deposition, carbon films, graphene structures.

PAGE 1426

NANOFLUID JET IMPINGEMENT HEAT TRANSFER

CHARACTERISTICS IN THE RECTANGULAR

MINI-FIN HEAT SINK

Paisarn Naphon and Lursukd Nakharintr

UDC 536.25

The nanofluid jet impingement heat transfer characteristics in a rectangular mini-fin heat sink are studied.

The heat sink is fabricated from aluminum by a wire electrical discharge machine. The nanofluid is a mixture

of deionized water and nanoscale TiO2 particles with a volume nanoparticle concentration of 0.2%. The results

obtained for nanofluid jet impingement cooling in the rectangular mini-fin heat sink are compared with

those found in the water jet impingement cooling. The effects of the inlet temperature of the nanofluid, its

Reynolds number, and the heat flux on the heat transfer characteristics of the rectangular mini-fin heat sink

are considered. It is found that the average heat transfer rates for the nanofluid as coolant are higher than

those for deionized water.

Keywords: jet impingement, nanofluids, rectangular mini-fin heat sink.

PAGE 1432

HEAT CONDUCTION AND HEAT TRANSFER IN TECHNOLOGICAL PROCESSES

ANALYTICAL SOLUTION OF THE STEFAN

PROBLEM WITH ACCOUNT FOR THE ABLATION

AND THE TEMPERATURE-DISTURBANCE FRONT

V. A. Kudinov, A. V. Eremin, and I. V. Kudinov

UDC 536.2(075)

An approximate analytical solution of the problem on the heat conduction of an infinite plate has been obtained

on the basis of the determination of the temperature-disturbance front and the introduction of additional

boundary conditions with account for the movement of the melting front in the case where the melted

substance is completely removed (Stefan problem with ablation). A method for construction of additional

boundary conditions, which allows one to obtain solutions of the indicated problem for engineering applications

in the form of simple algebraic polynomials free of special functions, is proposed. The accuracy of these

solutions is determined by the number of approximations, which is not limited in the case where additional

boundary conditions are used.

Keywords: integral methods, Stefan problem, temperature-disturbance front, melting front, heat of phase transition,

ablation, additional boundary conditions.

PAGE 1441

NONSTATIONARY END HEATING

OF A MULTILAYER SEMIINFINITE PLATE

I. N. Turchin

UDC 536.12

The solution of a two-dimensional initial boundary-value heat-conduction problem for a multilayer semiinfinite

band (plate) has been constructed with integral Laguerre and Fourier transformations. The results of a numerical

analysis of the temperature field in a three-layered plate as a function of the relative geometric and

thermophysical properties of the plate’s components have been given. The possibility of applying the method

proposed to analysis of temperature fields in bodies with nanocoatings has been elucidated.

Keywords: nonstationary heat conduction, multilayer plate, integral Fourier transformation, Laguerre polynomials.

PAGE 1453

THERMOPHYSICAL PROPERTIES

COMPENSATION EFFECT OF VISCOSITY

IN MULTICOMPONENT HIGH-MOLECULAR-WEIGHT

HYDROCARBON SYSTEMS

M. Yu. Dolomatov and S. V. Dezortsev

UDC 678.19:620.179.4

The presence of the compensation effect of dynamic viscosity for multicomponent systems produced in different

ways (physical mixing, chemical reactions) is established. The growth in the entropy term ΔS as part of the

preexponent of the Frenkel equation is accompanied by the change in the activation energy Ea of viscous

flow. An analysis of the available results shows that this phenomenon is universal in character for hydrocarbon

systems.

Keywords: compensation effect of dynamic viscosity, high-boiling oil fractions, activation energy of viscous flow,

entropy of activation of viscous flow.

PAGE 1463

DETERMINATION OF THE SURFACE ENERGY

OF A SOLID BY ITS CRITICAL SURFACE TENSION

V. M. Gasanov

UDC 541.12.012.4:532.612.3

The energy of solid surfaces of fluoroplastic, polyethylene, graphite, glass, and zinc at the solid–gas and

solid–liquid interfaces was determined by the critical surface energy of these substances in the case of their

complete wetting, where the equilibrium boundary wetting angle is equal to unity or zero. Equations for determining

the equilibrium boundary angle of wetting of the surface of a solid by the surface tensions at the

solid–liquid–gas interfaces without account for the gravitation and hysteresis effects are proposed.

Keywords: equilibrium boundary wetting angle, surface energy of a solid, interface energy.

PAGE 1469